Do you see this destroying prediction-based markets (i.e. the stock market and Polymarket)?
Markets exist because there's uncertainty about the future. If LLMs can predict with extremely high accuracy, would there no longer be a need for markets?
It is one thing to predict the future and have everyone not know about the predictions, but in a world where many people will be able to use LLMs to predict the future, the lower the quality of the predictions will be because they won't take into account that there are other agents predicting the future, which would influence the action of those agents, so you end up in a game theory scenario not that dissimilar from what we have now
I think you could simply shift the market 6 months in the future. no prediction system will be perfect for arbitrarily long horizons at reasonable cost.